An immediate morphopathologic response of neurons to electroshock; a reliable model for producing "dark" neurons in...

Ninety rats were electroshocked by a single condenser discharge 1 min. prior to perfusion fixation and delayed autopsy. Voltage and capacity of the condenser as well as surface area and position of the electrodes were varied between 125 and 1250 V, 20 and 200 microF, 2 and 24 mm2, and frontal to posterior, respectively. Within these ranges the electroshock rendered a varying number of brain neurons together with their dendritic arborization stainable by a special silver method. In toluidine blue preparations both somata and nuclei of these neurons appeared markedly shrunken and hyperchromatic, indicating morphological damage ("dark" neuron). A 250-V shock damaged only granule neurons of the hippocampal dentate gyrus. After a 750-V shock it was the substantia nigra, the lateral septal nucleus, the anterior amygdaloid area, and the lateral preoptic area that consistently contained electrically damaged neurons, without other kinds of parenchymal damage.